Wouldn't they mostly be draconic, considering their founder? I was just musing that clerics and paladins of the faith should know about as much draconic as the pope knows latin.
In fact, such characters that do not yet know the language probably should be required to learn it through CDQ before attaining the upper levels of faith. (PrCs and Epics at least)
Same for that matter, for clerics of many other faiths whith non-human gods. A human cleric of Vorax or Dorand might have a few translated works in common, but much of the greater texts of the faith would require them to eventually try to learn Dwarven. Katian clerics would either have to talk to a tree or speak animal, heh.
It'd be very cool if clerics did their rituals and prayers in the tongue of their god as much as possible. Weird chanting in languages you don't understand are a CONSTANT in world religions, heh.
